Matt Donnelly Senior Film WriterNetflix Original Films head Scott Stuber, a dogged producer who grew up in the studio system, has spent the bulk of his three years at the streamer barreling toward one goal — amass enough unseen features to give customers a new movie every week.That came to pass on Tuesday, as Netflix announced a staggering 71 titles for 2021 — a smattering of genres and ample star power, boasting names like Dwayne Johnson, Zendaya, Amy Adams, Chris Hemsworth, Melissa McCarthy,